Ignition circuit



K. s. JOHNSON IGNITION CIRCUIT Sept. 16, 195s Filed Feb. 1s. 195s United States Patent O IGNTION CIRCUIT Kaliu S. Johnson, Northviile, Mich., assignor to Holley Carburetor Company, Detroit, Mich., a corporation of Michigan Application February 13, 1953, Serial No. 336,698

3 Claims. (Cl. 123-148) The object of this invention is to replace the ordinary circuit breaker with transistors so that this ignition system for an internal combustion engine includes in its circuit transistors which control the operation.

The existing ignition system consists of A coil-the primary connected to a battery and the secondary connected to a distributor.

A make-and-break switch commonly known as a circuit-breaker, with a condenser across the two points.

A cam operating the circuit breaker which controls the primary of the coil. The diiculty experienced during the last forty-seven years with this construction is that:

The cam follower on the circuit-breaker wears and the tungsten points of the circuit-breaker burn away. Obviously, the life varies with the load. The slower the engine runs, the greater the current and the more the points burn away. The faster the engine runs and the less the current, the more important relatively is the Wear on the cam follower.

To adjust or replace the tungsten point occupies a large number of garage mechanics and adds considerably to the cost of the operation. If the circuit breaker can be eliminated, the car owner can afford to pay for a relatively expensive substitute because the upkeep will be less. Again, ignition systems usually fail just when the truck or bus is most needed.

'Figure 1 is a diagrammatic illustration of how my invention works with one or more point contact types'of transistors.

Figure 2 is a detail of an alternative construction showing how junction type transistors of the type n. p. n. can be used.

Figure 3 is a detail of an alternative construction showing how junction type transistors of the type p. n. p. can be used.

In all cases it is understood that a number of transistors coupled in parallel may be used to produce a powerful spark.

In Figure 1:

is the ground connection to the negative end of the battery 4, having a voltage equal to 6.3 volts.

l is the rotor of permeable material (soft iron) carried on a shaft 11 rotated by the engine. The rotor 1 has four arms.

2 is a coil wound around a core 12 of magnetic material having a pointed end which just clears the ends of the four rotating arms of rotor 1.

This assembly 14 is known as a pulse generator.

3 is the transistor which replaces the circuit breaker in general use.

The particular transistor shown in Fig. l is of the point contact type (comparatively weak) and consists of an `emitter 31 and a base 33 of a semi-conducting rectifying material such as germanium with certain critical impurities.

35 is a connector biased in the non-conducting end of the semi-conducting material of the base 33.

Germanium is the best material, although silicon can be substituted. Certain impurities are essential about which certain theories have been spun. Other rectifying crystal elements (other than silicon and germanium) may be substituted.

16 is the positive connection to the base 33 of the transistor 3 and to the coil 2.

17 is another connection for the coil 2 and leads from the positive end of battery 4 and to the emitter 31 of transistor 3 through the connections. The current from battery 4 divides; one fraction iiows through coil 2, the other goes direct to the emitter 31.

The current is abruptly interrupted as it tlows out of collector 35 and connection 20 to condenser 6 from the emitter 31 as the germanium acts as a rectifier so that the current cannot reverse its direction of ow. Now a pulse generator causes a current to alternate; that is, to reverse. lf this reversal is checked suddenly, we have the equivalent of a circuit breaker.

22 is a conductor which leads from the groundedplate of the condenser 6 and is grounded at ground connection 23.

Ignition coil 5 is connected to the collector 35, the conductor 20 and to the non-grounded side of the condenser 6 through conductor 24, which is located at the midway connection between the high tension and low tension coils of the ignition coil 5.

The low tension portion of coil 5 is also grounded through conductor 22.

26 is the high tension outlet from the high tension end of coil 5.

A distributor 7 distributes high tension electricity from 26 to a number of spark plugs, one of which is indicated at S and is grounded at 28.

By oscillating the coil 2 and its core 12 around shaft 11, the timing of the ignition can be varied; but that, of course, is no part of this invention.

ln Figure 2:

A junction transistor (type n. p. n.) is shown consisting of a base 30 made of a thin slab of p type germanium acceptors 32 is the emitter end of the junction made'of n type donors germanium.

34 is the collector end of the junction and is also made of n type excess of electrons germanium.

36 is the emitter.

38 is the collector.

The conductor 16 is connected to the base material 30.

The p type contains an excess of holes (according to the generally accepted theory) due to the presence of small quantities of impurities such as aluminum, boron, or indium (valency 3). Valency 5 impurities such as phosphorus, arsenic and antimony are present in small quanties in the n type (ends 32 and 34').

A modification of the electrical connections is required as compared with the electrical connection shown in Figure l, but the principle of construction is the same. Conductor 17 is connected to the negative end of the battery 4 and to the conductor 18.

In Figure 3:

In this example, a junction type of transistor of the p. n. p. type is used.

46 is the emitter connected to the p type at the end 42 of the central position 40 which is of the n type.

44 is also of the p type and is located at the other end of central portion 40, which is connected to conductor 16.

48 is the collector. Here, as in Figure 1, the positive terminal of the battery 4 is connected to the conductor 17 and to the emitter 46.

OPERATION F gure 1 As shaft 11 rotates, the magnetic lines in coil -2 and core 12 vary so there is an electric pulse transmitted to Patented Sept. 16, 1958v the transistor 3 which is abruptly interrupted by the rectifying characteristic of the transistor 3 as the arms of the rotor pass the pointed tip of the core 12 of coil 2.

This duplicates the action of a circuit breaker. rAfter the Figure 2 Here the polarity of the battery 4 is reversed; the central portion 30 of the p type is now connected to the negative end of the battery 4 (6.3 volts). Otherwise, the operation remains unchanged.

Figure 3 Here the polarity is the same as in Figure l so the operation is practically identical with that of Figure 1.

What I claim is:

l. In an ignition system of the character described an electrical circuit including a source of pulsating current consisting of a pulse generator having a rotating magnetic field and a coil in which the pulsating current is generated, a transistor having a base, an emitter, and a collector, a grounded battery supplying direct current connected to one terminal of the said coil of said'pulse generator and to the emitter of said transistor, the other terminal of said coil being connected to the base Vof 'said transistor 'a grounded ignition coil having primary and secondary coils with a common terminal therebetween, a condenser connected thereto in parallel with the primary coil of 'said ignition coil, said collector being also connected to said common terminal so that the single condenser is in parallel with the primary coil and connected through the transistor with said battery, and a high 'tension distributor connected to said Asecondary coil.

2. In an ignition system of the character described an electrical circuit including a source of pulsating current consistingof a pulse generator having a rotating magnetic eld and a coil in which the pulsating current is generated, a transistor having a base, an emitter element, and a collector element, a grounded battery supplying direct current connected to one terminal of the said coil of said pulse generator and to one of said elements, the other terminal of said coil being connected to the base of said transistor, a grounded ignition coil having primary and secondary coils with a common terminal therebetween, a condenser connected thereto in parallel with the primary coil of said ignition coil, the other of said elements being connected to said common terminal, so that the single condenser is in parallel with the primary coil, and connected through the transistor with said battery, and a high tension distributor connected to said secondary coil.

3. In an ignition system of the character described van electrical circuit including means for pulsating current,

a .transistor having a base, an emitter element, and a collector element, la grounded battery-supplying direct current connected to one terminal of said current pulsatingmeans and to one o'f said elements, the other terminal of said current pulsating means being connected to the base of said transistor, a grounded ignition coil having primany and secondary coils with a common connection therebetween, a condenser connected thereto inv parallel withthe primary coil of said ignition coil, the other of saidelements being connected in series with said primary coil, so that the single condenser is in parallel with the primary coil, and connected through the transistor with said battery, and a high tension distributor connected to said secondary coil.

References Cited in the tile of this patent UNITED STATES vPATENTS 2,353,527 Touceda et al July 1l, 1944 2,490';96`0 Hanchett Dec. i3, 1949 2,524,035 Bardeen et al. Oct. 3, 1950 2,624,016 White Dec. 30, 1952 OTHER REFERENCES Raisbeck: Electronics, December 1951, pages 12S-132, 134. 

